Dipyrromethane-Based PGeP Pincer Germyl Rhodium Complexes

Area of Science:

• Organometallic Chemistry
• Catalysis
• Main Group Chemistry

Background:

• Germylene ligands offer unique electronic and steric properties for stabilizing transition metal complexes.
• Rhodium complexes are widely employed as catalysts in organic synthesis.

Purpose of the Study:

• To synthesize and characterize a novel family of PGeP-pincer germyl rhodium complexes.
• To investigate the reactivity of these complexes with various reagents.
• To evaluate their potential as precatalysts for hydroboration reactions.

Main Methods:

• Reaction of a PGeP germylene ligand with rhodium precursors.
• Ligand substitution reactions to introduce different germyl groups (chloro, methoxy, methyl).
• Characterization of the resulting rhodium complexes using spectroscopic techniques.
• Catalytic testing in the hydroboration of vinylarenes with catecholborane.

Main Results:

• Successful synthesis of chloridogermyl, methoxidogermyl, and methylgermyl rhodium(I) complexes.
• Formation of pentacoordinate and hexacoordinate rhodium(III) complexes through reactions with various small molecules (CO, HCl, HSnPh3, Ph2S2, H2).
• Complexes 3 and 5 demonstrated catalytic activity in the hydroboration of styrene, 4-vinyltoluene, and 4-vinylfluorobenzene under mild conditions.

Conclusions:

• A versatile family of PGeP-pincer germyl rhodium complexes has been developed.
• These complexes exhibit diverse reactivity, allowing access to various oxidation and coordination states.
• The methylgermyl rhodium complexes show significant potential as efficient precatalysts for hydroboration reactions.